Much like Google’s custom search for websites, the mobile version can be branded with your own logo and design to make it feel for like your property. From there, users can search the Web as well as Google’s local, image, and news content.
Just as it does on the Web, Google dominates mobile search in terms of market share. Their mobile search experience is sparse and quick-loading, just like Web search. Extending this functionality to publishers, who can also generate revenue from adding Google mobile search, is simply a slam dunk.
As for how profitable this could be for publishers, the ads are naturally powered by AdSense for Mobile, which has already been in use for selling contextual ads on third-party mobile sites. Though the ad market might currently be weak, search typically performs better than contextual, so there is certainly money to be made here, both for Google and publishers.